1. Field of the Invention
The present invention relates to display devices for displaying characters, numerals, patterns and so forth. In addition, the present invention relates to electronic timepieces, such as wristwatches, stopwatches and so forth using the display devices. More specifically, the present invention relates to a display technology such as a liquid crystal device for displaying information by selecting one of the states of changing and not changing of a transmitted light polarization axis of a trasmitted linearly polarized light component.
2. Description of the Related Art
As a device for effecting display using external light, a digital-display-type timepiece using a liquid crystal device is most common. As such an electronic timepiece, one is conventionally known in which a first polarizer, a trasmitted light polarization axis changing optical element (transmitted light polarization axis changing means), such as a liquid crystal device, capable of selecting one of the states of changing and not changing a transmitted light polarization axis of a transmitted linearly polarized light component, a second polarizer, and a reflector plate are deposited in that order. In the liquid crystal device, for example, a TN (Twisted Nematic) liquid crystal, an STN (Super-Twisted Nematic) liquid crystal, an ECB (Electrically Controlled Birefringence) liquid crystal, or the like is used.
In the thus-constructed electronic timepiece (display device), both of the first and second polarizers transmit a linearly polarized light component in the direction of the transmitted light polarization axis of incident light, while they absorb a linearly polarized light component in the direction of an absorption axis intersecting perpendicularly to the direction of the transmitted light polarization axis. Accordingly, when the external light enters into the first polarizer and only the linearly polarized light component of the transmitted light polarization axis in a first direction enters into the transmitted light polarization axis changing optical element, one of the linearly polarized light component passing through an area for changing the transmitted light polarization axis, and the linearly polarized light component passing through an area for not changing the transmitted light polarization axis is absorbed by the second polarizer, and the other linearly polarized light component is transmitted by the second polarizer to reach the reflector plate. Therefore, only the light reflected by the reflector plate, that is, only the light passing through one of areas in the area for changing the transmitted light polarization axis and the area for not changing the transmitted light polarization axis of the transmitted light polarization axis changing optical element is transmitted by the transmitted light polarization axis changing optical element and the first polarizer, so that the time can be visually recognized.
In this way, according to the conventional electronic timepiece, only the light transmitted by one of the area for changing the transmitted light polarization axis, and the area for not changing the transmitted light polarization axis in the transmitted light polarization axis changing optical element is reflected by the reflector plate, and is transmitted by the transmitted light polarization axis changing optical element and the polarizer to contribute to display. In contrast, the light transmitted by the other area is absorbed by the second polarizer, or is transmitted by a polarization beam separation element, and does not contribute to display. Accordingly, the conventional electronic timepiece has a problem in that a segment portion or a background portion of the display is dark. In addition, for the same reason, the conventional electronic timepiece has a problem in that it is mechanically difficult to improve the esthetic design function of the electronic timepiece, such that it is difficult to make both the segment portion and the background portion mirrored, satined, or colored.
In view of the foregoing problems, an object of the present invention is to realize a display device which is constructed so that even a linearly polarized light component transmitted by any one of the area for changing a transmitted light polarization axis, and the area for not changing the transmitted light polarization axis is emitted toward a user, thereby effecting high visibility display utilizing external light, and which can effect reflective display with a combination of various textures and color tones, and to realize an electronic timepiece using the same.
In order to solve the above problems, in an exemplar of embodiment the invention, as shown in FIG. 1, firstly, a first characteristic of a display device 10 is that a first polarized-light separating member 2 for transmitting a linearly polarized light component polarized in a first direction of incident light and for not transmitting a linearly polarized light component perpendicularly intersecting the linearly polarized light component, a transmitted light polarization axis changing device 3 capable of selecting one of a first state of changing and a second state of not changing a transmitted light polarization axis when the incident linearly polarized light component is transmitted, a second polarized-light separating member 4 for transmitting a linearly polarized light component in a second direction of incident linearly polarized light components and reflecting a linearly polarized light component in a third direction perpendicularly intersecting the second direction, and a reflecting element 5 capable of reflecting the linearly polarized light component transmitted by the second polarized-light beam separating member 4 toward the second polarized-light separating member 4 are disposed in that order. In addition, according to the present invention, a second characteristic is that a modified layer (for example, a back-side coloring layer 71, a surface-side coloring layer 72, a back-side light-diffusing layer 91, and a surface-side light-diffusing layer 92) for emitting light incident on the second polarized-light separating member 4 by changing optical characteristics is formed on at least one of a surface 41 facing the transmitted light polarization axis changing device 3 of the second polarized-light separating member 4 and a back 42 facing the reflecting element 5.
In the thus-constructed display device 10, predetermined information can be displayed by first return light reflected by the reflecting element 5 to be transmitted by the second polarized-light separating member 4, the transmitted light polarization axis changing means 3, and the first polarized-light separating member 2, and second return light reflected by the second polarized-light separating member 4 to be transmitted by the transmitted light polarization axis changing device 3 and the first polarized-light separating member 2 in the light incident on the first polarized-light separating member 2 from the opposite side of the transmitted light polarization axis changing device 3.
That is, according to the present invention, each light transmitted by an area in the first state of changing the transmitted light polarization axis and transmitted by an area in the second state of not changing the transmitted light polarization axis in the transmitted light polarization changing device 3 is emitted as a linearly polarized light component (first return light) reflected by the reflecting element 5 to be transmitted by the second polarized-light separating member 4, the transmitted light polarization axis changing device 3, and the first polarized-light separating member 2, and as a linearly polarized light component (second return light) reflected by the second polarized-light separating member 4 to be transmitted by the transmitted light polarization axis hanging device 3 and the first polarized-light separating member 2, and contribute to display. Accordingly, for example, in an electronic timepiece or the like, since both a background portion and a segment portion can be brightly displayed with good contrast, there is an advantage of good visibility.
In addition, according to the present invention, the modified layer (for example, the back-side coloring layer 71, the surface-side coloring layer 72, the back-side light-diffusing layer 91, and the surface-side light-diffusing layer 92) for emitting light incident on the second polarized-light separating member 4 by changing optical characteristics is formed on at least one of the surface 41 facing the transmitted light-polarization axis changing device 3 of the second polarized-light separating member 4 and the back 42 facing the reflecting element 5, so that the modified layer imparts a hue or diffusibility to one or both of the first and second return light. Therefore, various combinations of texture and color can be realized, such that areas displayed by the first and second return light, for example, both the background portion and the segment portion of the electronic timepiece, can be colored, and highly versatile combinations of display forms are possible. For example, a form in which both the background portion and the segment portion are displayed in a colored mirror form, a form in which both the background portion and the segment portion are displayed in an orange peel form, a form in which one of the background portion and the segment portion is displayed in a colored mirror form and other one is displayed in an orange peel form, and so forth can be put into practice, so that an impression of high quality and the pleasure of displaying are increased. Moreover, since the modified layer is formed on the second polarized-light separating member 4, the number of parts is not increased.
In another exemplary embodiment of the of the modified layer is a surface-side modified layer (for example, a surface-side coloring layer 72, and a surface-side light-diffusing layer 92) formed on the surface of the second polarized-light separating member.
In another exemplary embodiment of the invention, the modified layer is a back-side modified layer (for example, a back-side coloring layer 71, and a back-side light-diffusing layer 91) formed on the back of the second polarized-light separating member.
In another exemplary embodiment of the invention, the modified layer includes at least a coloring layer (the back-side coloring layer 71, and the surface-side coloring layer 72) for emitting light incident on the second polarized-light separating member by changing a hue.
In another embodiment the invention, the modified layer includes at least a light-diffusing layer (the back-side light-diffusing layer 91 and the surface-side light-diffusing layer 92) for diffusing and emitting light incident on the second polarized-light separating member.
In another embodiment the invention, the modified layer is a composite layer including a coloring layer (the back-side coloring layer 71 and the surface-side coloring layer 72) for emitting light incident on the second polarized-light separating member by changing a hue and a light-diffusing layer (the back-side light-diffusing layer 91 and the surface-side light-diffusing layer 92) for diffusing and emitting light incident on the second polarized-light separating member.
In another embodiment of the invention, the modified layer is formed as a surface-side modified layer (for example, the surface-side coloring layer 72 and the surface-side light-diffusing layer 92) and as a back-side modified layer (for example, the back-side coloring layer 71 and the back-side light-diffusing layer 91) on both the surface and the back of the second polarized-light separating member, and the surface-side modified layer and the back-side modified layer mutually emit light incident on the second polarized-light separating member by changing optical characteristics into different types. With this configuration, a hue or diffusibility is imparted by both the surface-side modified layer and the back-side modified layer to the linearly polarized light component (first return light) reflected by the reflecting element 5 to be transmitted by the second polarized-light separating member 4, the transmitted light polarization axis changing device 3, and the first polarized-light separating member 2, whereas a hue or diffusibility is imparted only by the surface-side modified layer to the linearly polarized light component (second return light) reflected by the second polarized-light separating member 4 to be transmitted by the transmitted light polarization axis changing device 3 and the first polarized-light separating member 2. Therefore, highly versatile combinations of display forms are possible.
In another embodiment of the invention, each of the surface-side modified layer and the back-side modified layer includes at least a surface-side coloring layer 72 and a back-side coloring layer 71 for emitting light incident on the second polarized-light separating member by changing a hue into hues which differ from each other.
In another embodiment of the invention, each of the surface-side modified layer and the back-side modified layer includes at least a surface-side light-diffusing layer 92 and a back-side light-diffusing layer 91 for emitting light incident on the second polarized-light separating member by changing the light into diffusion patterns which differ from each other.
In another embodiment of the invention, at least one of the surface-side modified layer and the back-side modified layer is a composite layer including a coloring layer (the back-side coloring layer 71 and the surface-side coloring layer 72) for emitting light incident on the second polarized-light separating member by changing a hue, and a light-diffusing layer (the back-side light-diffusing layer 91 and the surface-side light-diffusing layer 92) for diffusing and emitting light incident on the second polarized-light separating member
In another embodiment of the invention, the surface-side modified layer is formed on an entire surface 41 of the second polarized-light separating member 4.
In another embodiment of the invention, the surface-side modified layer is formed only on a predetermined area in the surface 41 of the second polarized-light separating member 4. With this configuration, a hue or diffusibility is imparted by the surface-side modified layer to the light transmitted by an area where the surface-side modified layer is formed, regardless of whether the light is trasmitted by an area in the transmitted light polarization axis changing device 3 for changing a transmitted light polarization axis or by an area for not changing the transmitted light polarization axis. Therefore, if the surface-side modified layer is formed on the surface of the second polarized-light separating member as a pattern or a mark, the pattern or the mark to which a hue or diffusibility is imparted by the surface-side modified layer can be superimposed on the display formed by the first return light and the second return light. Therefore, the versatility of combinations of display forms becomes higher.
In another embodiment of the invention, wherein the back-side modified layer is formed on an entire back 42 of the second polarized-light separating member.
In another embodiment of the invention, wherein the back-side modified layer is formed on a predetermined area in the back 42 of the second polarized-light separating member 4. With this configuration, a hue or diffusibility is imparted by the back-side modified layer to the light transmitted by an area where the back-side modified layer is formed in the linearly polarized light component reflected by the reflecting element 5 to be transmitted by the second polarized-light separating member 4, the transmitted light polarization axis changing device 3, and the first polarized-light separating member 2. Therefore, if the back-side modified layer is formed on the back of the second polarized-light separating member as a pattern or a mark, the pattern or the mark to which a hue or diffusibility is imparted by the back-side modified layer can be superimposed on the display formed by the first return light. Therefore, the versatility of combinations of display forms becomes higher.
In another embodiment of the invention, the reflecting means is a partial reflection optical element for reflecting a part of an incident linearly polarized light component and transmitting other light, and includes a light source for a backlight capable of emitting light toward the reflecting means disposed between the second polarized-light separating member and the reflecting means at a position for sandwiching the reflecting means, and the display device is constructed so as to display predetermined information using a linearly polarized light component emitted from the light source for backlight and transmitted by the second polarized-light separating member, the transmitted light polarization axis changing means, and the first polarized-light separating member.
In another embodiment of the invention, the coloring layer is either a color filter layer or a dyeing layer attached to the second polarized-light separating member.
In another embodiment of the invention, the light-diffusing layer is either a corrugation formed on the second polarized-light separating member or a light-scattering coating film attached to the second polarized beam separation member.
In another of the invention, the transmitted light polarization axis changing device includes a liquid crystal device
In another embodiment the invention an electronic timepiece is constructed using the display device defined in any one the above exemplary embodiments.
That is, according to the present invention, the time and measurement results of time are displayed in digital form or in analog form by an area in the transmitted light polarization axis changing means selected in a state of transmitting by changing the transmitted light polarization axis of the linearly polarized light transmitted by the first polarized-light separating member and by an area selected in a state of transmitting with no change.